Add blocking: blocklists and block/allow rules with BIND response policy zones

jarld downloads blocklists (Adblock, hosts or plain domains), checks them
daily and reloads named only when a list changed; your own block and
allow rules take precedence, and the most specific rule wins. Lists and
rules apply per view (default: every view that offers recursion). Web UI
Blocking page with name checks, jarl blocklist and jarl block, the
/blocking API, blocked counts in the statistics. Database schema 6.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/server/h_changes.go

@@ -279,6 +279,9 @@ func (s *Server) status(w http.ResponseWriter, r *http.Request, p *auth.Principa
 		resp.Backup = s.backupStatus(r.Context(), now)
 		resp.TOTP = s.totpOverview(r.Context())
 	}
+	if p.Can(auth.Action{Resource: auth.ResBlocking}) {
+		resp.BlocklistErrors = s.blocklistErrors(r.Context())
+	}
 	writeJSON(w, http.StatusOK, resp)
 	return nil
 }